Linear unit



FIG. 1 is a side elevational view of a first side of a linear unit, showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a side elevational view of a second side thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is an end elevational view of a front end thereof; and,

FIG. 6 is an end elevational view of a rear end thereof.

The broken line showing of a pressure hose is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a linear unit, as shown and described. 